TURBULENT WAKE OF AN AXISYMMETRIC, SELF-PROPELLED BODY.

Since the available data for the wake structure of a self-propelled body indicate that the mean velocity defect and the turbulent velocity fluctuations do not decay along the axis at the same rate, the classical approach to obtaining similarity solutions using one velocity scale is not adequate. The new similarity solution given, which uses two empirically related velocity scales, can be more satisfactorily compared with the experimental results. Though the predicted decay rates for the velocity scales are somewhat low, the analytical results for the length scale l and for the turbulent shear, are in excellent agreement with the data. It is interesting to note that the turbulent velocity scale and the characteristic length scale for the self-propelled wake are similar to, respectively, the velocity and length scales for a finite momentum, axisymmetric wake.